First Epistle to the Thessalonians (Wikipedia) The First Epistle to the Thessalonians is a Pauline epistle of the New Testament of the Christian Bible. The epistle is attributed to Paul the Apostle, and is addressed to the church in Thessalonica, in modern-day Greece. It is likely among the first of Paul’s letters, probably written by the end of AD 52, in the reign of Claudius although some scholars believe the Epistle to the Galatians may have been written by AD 48.